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CHAPTER 7. THE DEVELOPMENT OF TRITICALE
F. J. ZILLINSKY
FIG.1. Scientists engaged in research on triticale, taken at the International Maize
and Wheat Improvement Center (CIMMYT) Headquarters, El Batan. Reading left
to right: N. E. Borlaug, CIMMYT; L. H. Shebeski, University of Manitoba;
A. Kiss, Hungary; A. Muntzing, Lund, Sweden; E. SAnchez-Monge, Madrid, Spain;
K. D. Krolow, West Berlin, Germany; E. Larter, University of Manitoba; F. J.
ous authors, but those Muntzing (1973a) and Briggle (1969) have been
used freely in the preparation of this manuscript.
Triticale is an artificially created derivative of a cross between wheat
and rye and possesses the chromosome complements of both parental species. There are two main groups of triticale: the octoploid triticales, which
are amphiploids of hybrids between hexaploid wheats and rye; and hexaploid triticales, which are amphiploids of hybrids between tetraploid wheat
and rye. Recently tetraploid forms have been reported (Krolow, 1973).
The first report of hybrids between wheat and rye was published by
Wilson in 1875. The hybrids were highly sterile and did not reproduce.
Rimpau, a German scientist, obtained a fertile, true-breeding strain from
a cross between bread wheat and rye in 1891. It was not until 1935 that
this strain was proved to be an amphiploid with 2n = 56 chromosomes
(Lindschau and Oehler, 1935; Muntzing, 1936).
According to Muntzing ( 1973a) an unusual outcrossing phenomenon
was observed in 1918 by Meister at the Saratov Experiment Station in
Russia. Thousands of natural wheat-rye hybrids occurred in wheat plots
which had been adjacent to rye plots the previous year. He reproduced
plants from these hybrids for several generations and eventually obtained
true-breeding, more or less fertile derivatives. In 1930 Meister gave a
botanical description of the new species and named it Triticum seculotricum surutoviense Meister. Lewistsky and Benetzkaja (193 1 ) produced cytological evidence that the new forms produced by Meister from the bread
THE DEVELOPMENT OF TRITICALE
wheat X rye crosses amphiploids with 2n = 56 chromosomes. They also
observed univalents and other meiotic irregularities. They assumed that
incompatibility existed among chromosomes between parental genomes.
Since disturbed pairing could not be due to a lack of chromosome homology, they believed that the amphiploids arose as a result of an apogamous
development of F, ovules having a somatic chromosome number and that
this was doubled during the first division of the egg cell.
In his review on early research on triticales, Muntzing (1973a) pointed
out that Lebedeff, working in the Ukraine, produced some rather advanced
cytological work in the early 1930’s. Lebedeff made investigations on
amphiploids that he had created as well as on those of his co-workers.
He suggested that the poor fertility found in the amphiploids was due to
the detrimental effects of inbreeding on the rye genome. This influence
might be avoided by using vigorous self-fertile rye parents. Lebedeff also
demonstrated the formation of unreduced ovules with 28 chromosomes
which produced a 35-chromosome plant when fertilized with rye pollen.
Lebedeffs work on triticale appears to have stopped in the mid 19303,
as did the work at the Saratov Experiment Station under Meister. It was
during this period that Lysenko was gaining a powerful influence in agricultural research in Russia.
Up to this time, triticale was more or less a biological curiosity, as it
appeared to have little or no potential as a commercial crop. Arne Muntzing, at the University of Lund in Sweden, began research on triticale in
1934 and has continued this work to the present time. His contributions
in cytology, genetics, and plant improvement in triticale have been outstanding. His work did much to encourage other scientists to undertake
triticale research. He not only produced new primary octoploid triticales
of his own and secondary forms from crosses between different octoploids,
but also developed a new form in 1933 which was produced by crossing
a tetraploid wheat, Triticum turgidum, with rye and pollinating the F,
hybrid with hexaploid wheat, A triple hybrid with 42 chromosomes resulted, possessing the complete genome of rye and a combination of chromosomes from bread and durum wheat (Muntzing, 1935). Nakajima
(1942) produced triple hybrids in the same way. Shulyndin at Kharkov
produced what he identified as 3-species hybrids, by crossing the F, of
common wheat X rye with durum wheat (Lukyanenko, 1972; Shulyndin,
Muntzing (1936) observed that occasionally F, plants of wheat-rye hybrids produce anthers having viable pollen. The viable pollen among these
anthers ranged from 20 to 60%. A plant having 56 chromosomes was
produced from controlled self-pollination with this pollen, thus providing
evidence that new amphiploids, which occur occasionally, arise from the
F. J. ZILLINSKY
spontaneous formation of small somatic sectors with a doubled chromosome number (Fig. 2 ) . This probably represents the mechanism by which
previous octoploids originated from sterile, haploid hybrids.
Muntzing (1939), reporting on triticale research between 1934 and
1939, observed that crosses between octoploid triticales from different
sources were not as cross-compatible as expected and that fertility of the
hybrids was quite low although the hybrids were vigorous. In later generations more-fertile recombinants could be obtained; these were more productive than the parental strains. He suggested the use of self-fertile ryes
as parents in the production of primary amphiploids to overcome sterility
B. THE DEVELOPMENT
Two important developments occurred during the late 1930’s that dramatically affected triticale research. First was the discovery that colchicine
could be used to induce chromosome doubling so that new amphiploids
could be produced routinely (Kostoff, 1938). Second, during the same
period improvements in embryo culturing had developed so that hybrids
could be obtained from normally cross-incompatible parental combinations.
These developments paved the way for the production of hexaploid triticales from hybrids between tetraploid wheat and rye (Fig. 3 ) .
The first hexaploid tritical was reported by Derzhavin (1938) from the
cross durum wheat x Secale montanum. A hexaploid triticale from a
durum wheat X cultivated rye, S. cereale, by O’Mara (1948) was to play
an important role in the development of triticale in North America and
Europe. Soon numerous new hexaploid triticales were being produced from
combinations of different tetraploid wheats and diploid ryes (Nakajima,
1952, 1958, 1963; SBnchez-Monge et al., 1956, 1959; Pissarev, 1963;
Kiss, 1966; Larter, 1968; Jenkins, 1969; etc.).
Muntzing (1972) indicated that the first hexaploids to be produced had
such poor seed development that researchers were not encouraged to work
on a form which appeared to have so little economic potential. However,
those produced by O’Mara and Sgnchez-Monge were more promising.
Breeding and Research in Eastern Europe
Some outstanding work on the development of triticale as a commercial
crop has been done by Arpad Kiss, a Hungarian plant breeder. Kiss started
his investigations on triticale in 1949. Using the species T . turgidum as
THE DEVELOPMENT OF TRITICALE
FIG.2A. Development of octoploid triticale.
Fro. 2B. Octoploid triticale and its parental forms.